Building a darkroom

So I'm planning on building a darkroom within short time. My grandpa was a photographer for a living and I'll get to use all his darkroom equipment, lucky me.
I plan on building it near the garage. I'm actually building the room from the ground up. I plan to insulate it, and have running water in it.
Question is, about how big should I make it? I don't want it huge, yet I don't want it small. My friend and I will be using it at the same time...

My darkroom is 3 feet by 4 feet... just enough room for me to have a spot to sit between the dry and wet side (and hang my coats when I'm not using it). It works for me.

On a more realistic scale.... If I were setting one up from scratch, I'd probably go at least 9 X 12 feet... enough space for two workbenches with four 3-foot wide "stations." However, if I'd ever had a real darkroom to work in, I'd probably say larger yet.

I'm not sure there is an "ideal" size. Most of us make do with whatever space we can carve out, so you learn pretty fast how to set up efficiently. More important is to try to get some outside ventilation if you can. If you have that and some running water, you will be in luxury!

Have you done a search for different plans or layouts? Think about all your equipment, storage, and look at the various ways to set up. That's a good way to get a rough idea about dimensions you'll need.

Alright. Seems the size I was thinking was about right. I plan on having one wet and dry side and just the walkway through the center. I got a lot of great plans from www.darkroomsource.net but I was just wondering other opinions/experiences.
And I definitely plan on setting up a nice ventilation system